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Solenoid Valve Seals

Seal / Diaphragm Material Selection.

Selecting the correct sealing material for your solenoid valve requires an understanding of available sealing materials. Seals are usually the most limiting factor of a solenoid valve. The seal selection should take the following items into consideration:

Chemical properties of the media

Temperature of the media

Pressure to be used

The next sections describe the most common seal materials available for solenoid valves. Usually more than one seal material is available for each valve type.

Connexion Developments Ltd cannot be held responsible for any information provided below. If you need more detailed information on chemical compatibility please contact us or your chemical supplier directly.

See full details of our Chemical Resistance Guide

Nitrile Rubber (NBR / Buna-N)

The chemical name for Nitrile rubber is Butadiene Acrylonitrile. However, most commonly it is referred to as NBR or Buna-N. NBR is probably the most common solenoid valve seal material and it is considered the standard material for neutral fluids by many. NBR is also the standard material for O-rings.

NBR can stand media temperatures to approximately 90 degrees Celsius on continuous basis, and higher temperatures intermittently. NBR resists ageing caused by heat very well. However, Nitrile Buna Rubbers resistance to sunlight is very poor. Abrasion and tear resistance of NBR is very good.

In addition to solenoid valve seals, NBR rubber is often used for water pump, carburettor, transmission, hydraulic pump, and hydraulic actuator seals.

NBR seals are most commonly used with the following media:

Water

Air

Different Fuels, Oils, and Gases

NBR has a good resistance to:

Aliphatic hydrocarbons

Petroleum

Fuels

Mineral Oil

Vegetable Oil

Hydraulic fluids

Alcohol

Many Acids

Abrasion

NBR has a poor resistance to:

Ozone

Acetone

Methyl Ethyl Ketone

Chlorinated Hydrocarbons

Ethers and Esters

EPDM Rubber

EPDM stands for Ethylene Propylene Diene Monomer rubber. EPDM solenoid valve seals are well suited for use with hot water due to EPDM's excellent resistance to heat. The maximum service temperature of EPDM is approximately 120 degrees Celsius. EPDM is unsuitable for use with most oils and fuels.

EPDM seals are most commonly used with the following media:

Hot /Cold Water, Steam

Freon

Air

EPDM has a good resistance to:

Heat

Ozone

Oxidizing Chemicals

Up to Medium Concentration Acids

Alkali's

Fireproof hydraulic fluids

Many Ketones and Alcohols

Sunlight

Abrasion and Tearing

EPDM has a poor resistance to:

Most Oils and Fuels

Hydrocarbons

Aromatic and Aliphatic Hydrocarbons

Halogenated Solvents

Concentrated Acids

Viton® (FKM)

Viton® (FKM) is a brand name for the Fluoroelastomer manufactured by DuPont. It is well know for its excellent heat resistance, making service temperatures nearing 150 degrees Celsius possible.

FKM seals are most commonly used with the following media:

Hot Water

Acid

Alkali

Oils

Hydrocarbon

Salts Solutions

Viton® (FKM) has a good resistance to:

Hydrocarbons

Many Aggressive Chemicals

Diluted Acids

Weak Alkalis

Mineral Oils

Aliphatic and Aromatic Hydrocarbons

Chlorinated Hydrocarbons

Sunlight

Ozone

Viton® (FKM) has a poor resistance to:

Ketones

Acetone

PTFE - Polytetrafluoroethylene

PTFE is a Polytetrafluoroethylene. The most well known trademark of PTFE is DuPont Teflon. PTFE is practically resistant to all fluids. PTFE is non-elastic, limiting its use in certain applications. PTFE can be used with media reaching very high temperatures 230 degrees Celsius.

Connexion Developments Ltd have access to many other types of seal material including metal/metal and metal/Resin and FFKM amongst others for more aggressive and demanding applications.

Please also keep in mind that apart from the dry armature valves most valves will have varying grades of stainless steel in contact with the media. i.e. 303 or 302 stainless steel springs, 304 stainless core tube and stainless steel 430F Armature. Please consult our seal material guide for more information